Bag closure



Nov. 18, 1930. i. w. LITCHF'IELD 1,782,240

BAG CLOSURE Filed Jan. 5. 1328 INVENTOR [54 46 1/ [/76/9/"7620 TTORNEYS Patented Nov. 18, 1930 UNITED STATES PATENT OFFICE ISAAC W. LITCHFIELD, OI BOSTON, MASSACHUSETTS, ASSIGNOB TO IBEMIS BRO. BAG

COMPANY, A CORPORATION OF MISSOURI BAG- CLOSURE Application filed January 5, 1928.

This invention relates to flexible containers such as bags, and particularly to containers for use in packaging materials which come in finely divided or powdered form and which are usually bagged in fairly large bulks, such,

for example, as cement, 'lithopone, etc.

Until comparatively recently such finely powdered, heavy and bulky materials have usually been bagged in fabric bags, pasted paper bags, being usually not sufficiently strong to withstand the strains to which bags of these bulky and often heavy materials are subjected in handling, even when the paper bag is made up of several paper bags, one within the other. Paper bags having their ends closed by stitching, staples or other forms of through and. through fastenings have also given considerable trouble, even when made with several interliners, both because of the tendency of the material to sift through the stitch or staple holes, and because of the tendency of the stitching or stapling to break out when the bag, filled with cement or other bulky material, is dropped or otherwise roughly handled.

Various improvements have been made in the bags used for bulky, finely divided mate rials in order to overcome the tendency to sifting of the powdered material through the openings made by the securing fastenings and to increase the resistance of the closure to pulling through of the fastenings, some of which improvements have been very effective, such, for example, as the closure which is formed by folding the end of the bag against one side and then reversely folding the overlapping parts against the other side of the bag thereby reinforcing each side wall of the bag by at least two thicknesses of the bag at the point where the fastenings are applied. These improvements have, to a considerable extent, solved the problem of sifting and have increased the resistance of the fastenings' to pulling out or enlarging the openings, but they have not entirely solved the problem of providing a satisfactory paper bag of reasonable cost for handling cement and other bulky and frequently heavy powdered materials.

An object of the present invention is to pro- Berial No. 244,691.

vide a bag closure which will so effectively resist the strains tending to disrupt the closure as not only to make the bag practically an equivalent of fabric bags for most condltions under which the materials to be bagged are handled, but also to permit the construction of an efiicient and satisfactory bag for such materials of a considerably smaller number of thicknesses of paper, that is, with a considerably smaller number of interliners, than has heretofore been considered practicable.

More particularly, the invention aims to provide a strong durable and preferabl dustproof closure, particularly adapted or use with paper bags, which is so simple in its construct-ion and mode of formation that it lends itself to 'mechanical manipulation, whereby it can be produced by machinery at a relatively small cost.

One of-the primary purposes of the closure construction herein shown is to prevent the pressure of the material in the bag, or of the air pressure, due to sudden shifting of the material, as, for-example, when thebag is dropped with the material in it, from exerting a spreading action directly upon the closure seam. In ordinary closure constructions heretofore employed with paper bags for bulky materials, particularly for finely divided or powdered materials such as cements, the seam formed by the securing means has been so arranged that the pressure of the material or of the air in the bag upon the walls of the bag has been transmitted through both walls directly to the seam as a seam-spreading movement of these walls, with the result that the strain has come directly upon the securing fastenings. Not. only does this strain upon the securing fastenings tend to open up the fastening openings of the bag thus permitting leakage of the material, but these strains, when repeated, usually result in the fastening means being pulled through the bag walls thus causin the bag closure to be broken open.

y the present invention-the closure is so formed that pressure of the material in the bag or of pocketed air on the walls of the bag in the region of the closure is not transmitted to the seam as a seam-spreading strain, but, instead, the pressure tends to rock the whole closure about an axis adjacent to the fastening line and in a flexible wall of the bag whereby the seam ispositioned out of the line of the direct thrust of the material or of the pocketed air, the force of which is taken up directly by the bag walls and is thus not transmitted to the seam as a seam-spreading strain.

Other objects and important features of the invention will appear from the following description and claims when considered in connection with the accompanying drawings, in which Figure 1 is a side elevation of a bag having the invention incorporated therein, the closure being shown in the position which it assumes when the 'walls of the bag have been distended;

Fig. 2 is a section through the novel closure p51 t-Cl116 present invention before the bag is Fig. 3 illustrates the position the closure assumes When the walls of the bag have been distended by the material with which the bag has been filled or by pocketed air;

Fig. 4 is a modification of the construction shown in Fig. 2.

In the preferred embodiment of the invention illustrated in Figs. 1 to 4 inclusive, the invention is shown as so applied to a bag closure of the type of that hereinabove referred to, which comprises a fold of the end of the bag to one side thereof and a reverse fold of the overlapping parts to the other side of the bag, that all of the advantages of this type of bag closure, so far as reinforcement of the walls of the bag at the closure end are concerned, as well as the sift-proof advantages of the said closure, are obtained and at the same time a construction is provided in which the pressure of the material in the bag or of the pocketed air on the walls of the bag, instead of being transmitted to the closure seam as a seam-spreading strain. tends to rock the whole closure about an axis adjacent to the line of fastenings by which the closure is secured and in one of the flexible walls of the bag, whereby the seam is positioned out of the line of the direct thrust of the material or of the pocketed air, the force of which is taken up by the bag walls.

In the illustrated construction, the bag 2, which may be of any usual bag construction, material and size, with the exception of the novel closure now to be described, has its side walls, at the end which is to be closed, brought together and thenfolded into the position shown in either Fig. 2 or Fig. 4, in any suitable manner as, for example, by first folding the end of the bag over upon the left hand side ..f the bag, as shown in Figs. 2 and 4, to

form the fold 4, and then reverselyrfolding the overlapping parts -over upon the right hand side of the bag to form the fold 6. The folded-over parts are then secured in their folded condition, preferably by thru-andthru fastenings such, for example, as staples 8. These staples preferably extend in a line across the end of the bag, as shown in Fig. 1. From the foregoing description it will be seen that this closure provides upon the outside of the left hand wall of the bag in Figs. 2 and 4, at least two thicknesses of reinforcing material at the closure and upon the right hand wall in Figs. 2 and 4, at least four thicknesses of reinforcing material.

In the preferred embodiment of the invention, advantage is taken of the fact that there is considerable reinforcing of the bag wall on one side of the closure, so to form the closure that when the bag is distended, either by the material with which the bag is filled or by the pocketed air, which may be driven ahead of the material, pressing upon the bag wall adjacent to this reinforcing, this pres-' sure will tend to rock the closure as a whole about a line of fiexure in the other wall of the bag. In the form of the invention shown in Fig. 2, the reinforcment formed by the reverse fold is so extended on the bag side of the line of staples 8, as shown at 10, as to give considerable leverage to the pressure of the material in the bag on the Wall 12, which tends to rock the closure about a line of fiexure in the opposite Wall 14.

Where the reinforcement 16 formed by the initial folding over of the bag end does not extend much beyond the line of fastenings 8 on the bag side of this line, as in Fig. 4, and the reinforcement 10 formed by the reverse fold does extend, as shown in Fig. 4, a considerable distance beyond the line of fastenings on the bag side of this line, the tendency will be, when the pressure of the material begins to separate the walls 12 and 14, for the lever arm 10, formed by the reverse fold reinforcement, to rock the closure as a whole about a line of fiex-ure in the wall 14 closely adjacent to the end of the reinforcement 16. When, however, as shown in Figs. 2 and 3 of the drawings, the reinforcement 16 is extended somewhat beyond the line of fastenings 8, it will be sometimes desirable, particularly if the paper or other material of which the bag is formed is comparatively stifl', to weaken the reinforcement, as at 17, along the line about which it is desired that the closure shall rock, this line being usually preferably adjacent to the line of. fastenings 8. Such a weakening or permanent set of the reinforcement 16 is illustrated in Fig. 2.

From the foregoing description, it will be seen that when the walls 12 and 14 of the bag are spread by filling, or in any other manner which brings pressure to bear upon them, the greater leverage provided by the reinforcement or lever arm 10 will cause the parts to assume the position shown in Fig. 3. This action may consist merely in the lever arm- 10 rockmg the closure about a line of flexure in the wall 14 as a fulcrum, or by the wall 14:.

. vention it is to be understood that the invention is not in any way limited to any one or a few particular form or forms but may be embodied in other forms and that many modifications may be made within the scope/of my invention.

Fromthe foregoing description, it will be seen that, the invention, particularly in its preferred form illustrated in Figs. 1 to 4 inclusive, provides an effective sift-proof anddurable closure for flexible containers such as bags for cement, lithopone, etc., and thus makes possible the use for such materials of paper bags in place of the fabric bags heretofore required.

What is claimed as new is:

1. A bag closure formed by a fold of one end of the bag upon itself to one side of the bag, fastenings securing said end in its closed and folded condition, the folded-over portion of the bag being extended on the bag side of the fastenin line a sufficient distance beyond a line of exure in the other side of the bag adjacent to the fastening line to constitute with said fastenings a lever tending to rock said closure about said line of flexure :and means on the other side of said bag adjacent the fastening line adapted to establish said line of flexure.

2. A bag closure formed of a fold of one end of the bag upon itself to one side of the bag, a. reverse fold ofthe overlapping parts against the other side and means fastening the parts in said folded condition, one of said folds being so extended on the bag side 'of the fastening means beyond the-line of flexure in the opposite bag wall as to form a lever tending to rock the closure about such line of flexure.

3. A bag closure comprising a fold of one 1 end of the bag upon itself to one side of the 9 bag, a reverse fold of the overlapping parts against the other side and means fastening the parts in said folded condition, the reverse fold being so extended on the bag side of the fastening means beyond the line of flexure in the opposite bag wall as to form a levertending to rock the closure about such line of flexure.

4. A bag closure comprising a fold of one end of the bag upon itself to one side of the bag and a reverse fold of the overthe bag lapping parts against the other side of the bag, whereby one side of the bag is reinforced with at least two thicknesses and the other side with at least four thicknesses, and meansfor confining the parts in folded condition, said fold of four thicknesses being so extended on the bag side of the fastening means beyond the line of flexure in the opposite bag wall as to constitute a lever tending to rock the closure about such line of flexure.

5. A bag closure comprising means for securing the walls of the bag together along a fastening line extending crosswise of the bag, means also secured in position as a part of the closure by said securing means and about a line of flexure in the other wall when the material in the bag spreads said walls, and means secured closely to said other wall along said fastening line adapted to hold said bag wall against bending and to distribute the force of said securing means over the bag wall to hold said bag wall against bending into but not substantially beyond said line of flexure.

6. A bag closure comprising a port-ion of the end of a bag having its walls brought together and secured near said end, one wall portion on the bag side of the securing means being left free to flex to a line of flexure adjacent the securing means but supported against flexing from said line of flexure to and beyond the securing means and the opposed wall portion of said bag being so reinforced about said securing means and on side thereof as to act under the pressure 0 the material in the bag to rock said ClOfilTG about said line of flexure in the other wa 'Z. A bag closure formed of a fold of one end of the bag upon itself to one side of the "end of the bag upon itself to one side of the bag, a reverse fold of the overlapping parts against the other side, and means fastening the parts in folded condition, one of said folds being so extended on the bag side of the fastening means as to form a lever tending to rock the closure about a line of flexure inthe opposite bag wall, said last-mentioned bag wall and any. overlapping part of the closure being scored to form a predetermined line of flexure.

9. A bag closed at one end by a fold of its end back over one side and a second fold back over the other side, and fastening means through said folds along a line parallel to the end of the bag, the fold on one side of the bag terminating close to the line of the fastening means in a straight edge adapted to form an abutment for creasing the bag and the fold on the other side extending a substantial distance on the bag side of said fastening means and being of suflicient stifiness to act as a lever to fold the bag along the straight edge of the other fold.

10. A bag closed at'one end by av fold thereof back onto itself comprising means reinforcing the material of the bag about its fastening and adapted to form an abutment which defines a line of flexure on the bag side of said fastening, reinforcing and stiffening means on the other side of the bag about the fastenings extending on the bag side of said'fastenin a substantial distance beyond said line of exure and adapted to act as a lever to bend said bag, and fastening means securing together the bag, the reinforcin abutment and the reinforcing and stiffening lever close to said line of flexure.

11. A bag closure comprising stifiening means extendin from adjacent the end of the bag for a su stantial distance along one side of the bag and adapted to withstand bending by the pressure of the material in the bag, stiffening means on the other side of the bag adapted to establish a line of flexure for said other side of the bag substantially within the area of the first named stiffening means, and means for securing said stifienin means to ether in clamping relation to t e end of t e bag.

12. A closure as defined in claim 11 in which the securing means is along a line close to the. line of flexure, spaced slightly toward the end of the bag.

13. A bag closure comprising means for securing the walls of the bag together near its end, means engaged by said securing means for distributing the force of said securing means over the end of said bag wall and means serving to convert the outwardly directed force of the contents against the bag wall into a turning moment adapted to turn the closure into a plane transverse to the axis of the bag.

Signed at Boston; Massachusetts, this 27th day of December, 1927.

- ISAAC W. LITOHFIELD.

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